/*
 *    AudioFormats.java
 *
 *    This file is part of Tritonus: http://www.tritonus.org/
 */

/*
 *  Copyright (c) 1999,2000 by Matthias Pfisterer
 *  Copyright (c) 1999 by Florian Bomers <http://www.bomers.de>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as published
 *   by the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/*
|<---            this code is formatted to fit into 80 columns             --->|
*/

package org.klab.packetcast.audio;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;



public class AudioFormats
{
      private static boolean doMatch(int i1, int i2)
      {
            return i1 == AudioSystem.NOT_SPECIFIED
                  || i2 == AudioSystem.NOT_SPECIFIED
                  || i1 == i2;
      }



      private static boolean doMatch(float f1, float f2)
      {
            return f1 == AudioSystem.NOT_SPECIFIED
                  || f2 == AudioSystem.NOT_SPECIFIED
                  || Math.abs(f1 - f2) < 1.0e-9;
      }



      /**
       * Tests whether 2 AudioFormats have matching formats.
       * A field matches when it is AudioSystem.NOT_SPECIFIED in
       * at least one of the formats or the field is the same
       * in both formats.<br>
       * Exceptions:
       * <ul>
       * <li>Encoding must always be equal for a match.
       * <li> For a match, endianness must be equal if SampleSizeInBits is not
       * AudioSystem.NOT_SPECIFIED and greater than 8bit in both formats.<br>
       * In other words: If SampleSizeInBits is AudioSystem.NOT_SPECIFIED
       * in either format or both formats have a SampleSizeInBits<8,
       * endianness does not matter.
       * </ul>
       * This is a proposition to be used as AudioFormat.matches.
       * It can therefore be considered as a temporary workaround.
       */
      // IDEA: create a special "NOT_SPECIFIED" encoding
      // and a AudioFormat.Encoding.matches method.
      public static boolean matches(AudioFormat format1,
                              AudioFormat format2)
      {
            //$$fb 19 Dec 99: endian must be checked, too.
            //
            // we do have a problem with redundant elements:
            // e.g.
            // encoding=ALAW || ULAW -> bigEndian and samplesizeinbits don't matter
            // sample size in bits == 8 -> bigEndian doesn't matter
            // sample size in bits > 8 -> PCM is always signed.
            // This is an overall issue in JavaSound, I think.
            // At present, it is not consistently implemented to support these
            // redundancies and implicit definitions
            //
            // As a workaround of this issue I return in the converters
            // all combinations, e.g. for ULAW I return bigEndian and !bigEndian formats.
/* old version
*/
            // as proposed by florian
            return format1.getEncoding().equals(format2.getEncoding())
                  && (format2.getSampleSizeInBits()<=8
                      || format1.getSampleSizeInBits()==AudioSystem.NOT_SPECIFIED
                      || format2.getSampleSizeInBits()==AudioSystem.NOT_SPECIFIED
                      || format1.isBigEndian()==format2.isBigEndian())
                  && doMatch(format1.getChannels(),format2.getChannels())
                  && doMatch(format1.getSampleSizeInBits(), format2.getSampleSizeInBits())
                  && doMatch(format1.getFrameSize(), format2.getFrameSize())
                  && doMatch(format1.getSampleRate(), format2.getSampleRate())
                  && doMatch(format1.getFrameRate(),format2.getFrameRate());
      }

      /**
       * Tests for exact equality of 2 AudioFormats.
       * This is the behaviour of AudioFormat.matches in JavaSound 1.0.
       * <p>
       * This is a proposition to be used as AudioFormat.equals.
       * It can therefore be considered as a temporary workaround.
       */
      public static boolean equals(AudioFormat format1,
                              AudioFormat format2)
      {
            return format1.getEncoding().equals(format2.getEncoding())
                  && format1.getChannels() == format2.getChannels()
                  && format1.getSampleSizeInBits() == format2.getSampleSizeInBits()
                  && format1.getFrameSize() == format2.getFrameSize()
                  && (Math.abs(format1.getSampleRate() - format2.getSampleRate()) < 1.0e-9)
                  && (Math.abs(format1.getFrameRate() - format2.getFrameRate()) < 1.0e-9);
      }

}



/*** AudioFormats.java ***/
